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The Me Generation

Despite conservation efforts to ensure its survival, an island bird species has remained endangered because of its own social behaviors. The Seychelles magpie robin, whose population dwindled to just seven breeding pairs in 1988, has been the subject of intense conservation efforts for more than three decades. Success has been modest, with reintroductions within the Seychelles archipelago boosting the population size to almost 150 individuals in all. López-Sepulcre et al. show that recovery has been slower than expected because of competition within territorial social groups consisting of a dominant breeding pair and several subordinate individuals, whose reproduction is postponed until one of the dominant pair dies or is competitively ousted. Competitive interactions for dominance within the group reduce the group's reproductive output. Thus, behavior that is advantageous for an individual's fitness (and evolutionary success) can be detrimental to that of the group. Simulations suggest that recovery of the population would have been at least one-third more rapid in the absence of competitive interactions, highlighting the need to take social behavior into account in species recovery plans.— AMS